Hey Hoser , interesting way you have to clean a very stuborn coin . Do you have a before and after pic ? I am very intrigued .Personally, I would leave it be. Oh yeah, a light cleaning with a soft brush, soap and water. However, if you want to try to bring out more detail boiling Hydrogen Peroxide would be my choice. Good luck.
Not sure if you were thinking that was the same coin in the illustration or not but what you have is a 1793-1796 Liberty cap and not a Draped bust. I hope you were able to save it as every large copper cent I tried to usually resulted in a unrecognizable coin that I wish I had left alone.There isn’t much left of it. I have an electrolysis unit, but I’m guessing that’s not the best way to go.